A variety of input devices are being used to operate a computing system. For example, input devices like a button, a key, a joystick and a touch screen are being used. Since the touch screen is easy and simple to operate, the touch screen is increasingly being used to operate the computing system.
The touch screen may include a touch sensor panel which may be a transparent panel with a touch-sensitive surface. Such a touch sensor panel is attached to the front side of a display screen, and then the touch-sensitive surface may cover the visible side of the display screen. The touch screen allows a user to operate the computing system by simply touching the display screen with a finger, etc. In general, the touch screen recognizes the touch on the display screen and touch position, and then the computing system analyzes the touch and performs operations in accordance with the analysis.
Here, there is a requirement for a touch input device capable of increasing the signal to noise ratio in accordance with the change of the capacitance change generated by the touch on the touch sensor panel and of solving the rear touch problem.